GNRH1 and ovarian hyperstimulation syndrome: GnRH antagonists have several advantageous effects over GnRH agonists [6], [7], of which the most important is having fewer follicles and lower oestradiol level on the day of human chorionic gonadotropin (hCG) application [4] leading to a lower incidence of ovarian hyperstimulation syndrome (OHSS) [8], a serious complication of assisted reproductive therapy.